[tsm554]

Hi all,

I'm currently trying to setup a CFD model for investigating heat transfer for a medical problem. I have some CT and MRI scans from which I have created separate volumes of the head, skull, brain etc. using software called Amira. I now want to import them into Gambit then subtract the skull from the head and so on so that I can form the full head and mesh it. For the subtraction I need each volume to be real.

The problem is most of the time I import a mesh (STL format) it is not recognised as a volume and the faces cannot be stitched together as at least one face cannot be converted to real (often this is the face called boundary wall). Occasionally the mesh is recognised as a volume but cannot be converted to real again because one face cannot be converted.

One of the volumes which is fairly simple did actually fully work and get converted to real. I also tried an experiment where I made a short cylinder in Amira, when I remeshed it and simplified it in Amira (it looked really neat in Gambit) I had the same problem but when I left the cylinder as it was originally (around 70000 triangles) I could make a real volume with it.

From everything I have tried to get it to work the problem occurs almost every time even with simple geometrys apart from the 2 times described. It seems from this an almost random problem but simpler not remeshed volumes are more likely to work.

If anyone has any ideas what might be causing this, has had a similar experience or has a way of getting round this I would be really grateful. It would be a great help to me but also could have some impact on clinical practice in hospitals as well.

Thanks a lot,
Tom